DE2608149A1 - HEADPHONE SYSTEM - Google Patents

Description

Patent attorneys

Dipi.-lng. Linen weaver

Dkl-m. ΖίΠΊΓ.βΓΕΠίίηπ _{o1 / ß}

WpL-bg. ». Wencjcrsliy 2608149

Munich 2, Ro "* nt * 17
ToL 2603989

February 27, 1976 A1208-03

MiLTSUSHITA ELECTSIC INDUSTRIAL CO., LTD. Osaka, Japan

The JJrfindunt refers to a headphone system that is connected to a playback device for head monitoring with which output can be made from a program source, for example from a record, a magnetic tape or the like, or that can also be connected to an acoustic device such as a radio receiver or similar. can be connected.

The invention has for its object to star a headphone sy create in which the same sound image as with a loudspeaker monitoring arises because the sound image is localized outside the head, although the listener actually wears headphones, so that the There are no signs of fatigue occurring after long-term headphone listening.

Another object of the invention is to provide a headphone system to create, in which the sound image can be easily influenced with regard to the perception of distance and calibration, since this is done only an adjustment of attenuators is required.

609882/0712 -

The above and other features and gate parts of the invention can be derived from the following detailed .Be description based on of the enclosed drawings. Ss show:

1 shows an arrangement for the case of loudspeaker hearing;

Pig. 2 an arrangement for the pail of the Ko ρ fab listening %

3 shows a diagrammatic representation of the sound paths in the loudspeaker before hearing;

Fig. 4 is a block diagram of the essential components of a Embodiment of the headphone system according to the invention *

FIG. 5 is a block diagram of another embodiment of FIG Invention;

Fig-. 6 is a block diagram showing a modification the embodiment shown in Fig. 5;

Figure 7 is a graph of the between levels differentiated between the left and right ear and the sense of direction relationships existing in a sound image »

FIG. 8 is a diagram of a circuit used to achieve the characteristics shown in FIG. 7;

Fig. 9 ^e i ⁿ block diagram of another embodiment of the invention ^

Fig. 10 is a cross-sectional view of one in the present invention Headphone system headphones used:

11 is a graphic representation of the equivalent circuit for the headphones shown in FIG.

12 shows a graphic representation of the sound pressure-frequency characteristics measured on headphones; and

13 and 14 are block diagrams of further embodiments the invention.

The illustration of FIG. 1 relates to the case of Play from a program source such as a vinyl record or a magnetic tape, with eavesdropping by a listener in a

609 882/0712 ^closed

closed room via loudspeaker. In Fig. 1 denotes the Reference number 1 a playback system for playback from a program source, with the reference numerals 2 and 5 are loudspeakers for converting the left and right signals in the playback system 1 as de rge ge be new denoted in sound waves, at 4 the listener is shown and at and 6 the ears of this listener are shown. BLe from the speakers 2 and 3 outgoing sound waves reach the ears 5 and 6 of the Listener 4, which an acoustic image, for example at a point A perceives, namely in a place outside of his head.

Pig. 2 shows the arrangement for the case of medication from the same program source as in Fig. 1 with the aid of the ■ playback system 1, but for listening with headphones 7 · In the case of the Headphone, as shown in Fig. 2, the listener takes an acoustic image or sound image at a point B, for example true that lies within his head. In Fig. 2 are with the Reference numerals 8 and 9 denote sound transducers arranged on the right side and on the left side of the headphones 7, respectively.

As can be seen from the above, there is between the loudspeaker monitoring, as it is shown in Fig. 1, and that in 2 shows a fundamental difference in the localization of the sound or audio image.

The mentioned difference between the loudspeaker monitoring and the pigtail wiretapping is due to the following two circumstances:

(a) a lack of information in headphone listening and

(B) Peculiarities of the headphones themselves.

Ss should now be dealt with first on point (A).

Fig. 3 is a pictorial representation of the operations when listening to loudspeakers in a closed room-10. The from The sound emitted by the loudspeaker J propagates along various Sound paths from (hereinafter referred to as sound lines), for example that is, along the sound lines 11, 12 and 13, and thus arrives at the right ear 5 and the left ear 6 of the listener. Here represent the sound lines 11 those sound we ge on which the

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2608H9

radiated from the speaker 3 Sehall iie ears 5 and 6 is reached in a very short time, ie the direct sound we ge, whereas the scarf lines lie 12 and 15 that "denote on which the outgoing from the speaker 3 Sound m. ch Se flexion at the Walls of the room IO reaches ears 5 and 6, in other words, these are some of the indirect sound paths. Not only does indirect sound reach ears 5 and 6 later than direct sound, but these sound waves are mostly against each other a phase difference, for example between a sound wave hitting the left ear 6 and a sound wave hitting the right ear 5, since there is a phase shift with every reflection on the walls as well as due to the acoustic asymmetry of the llaum.

3ei! U listening with headphones; like it in Pig. 2 is shown, In contrast, there is no indirect sound, which is only possible with the Loudspeaker monitoring is the case, and the acoustic image is therefore built in head itself.

An electrical circuit in which a signal is generated will now be described with reference to FIG. 4, which corresponds to the indirect sound in the case of loudspeaker monitoring (hereinafter referred to as indirect audio frequency signal), whereupon this indirect audio frequency signal with another signal = e mi see which corresponds to the direct sound (hereinafter referred to as the direct audio frequency signal), to then the delete signal to the headphones to feed.

Fig. 4 shows an inventive headphone system in which playback for listening to a program from a program source with a In Fig. 4, reference numeral 14 denotes an input terminal to which a monaural signal is inputted appears, with reference numerals 15 and 15 'being delay circles and with the reference numerals 16 and 16 'phase shifter with different frequency-phase characteristics. ELe delay circles 15 and 15 'set with the phase shifters 16 and l6' Reverberation circuit η. With the reference numerals 17 and 17 'are adders and the reference numerals 18 and 18 »denote adders.

609882/0712

7 / ie from Fi «·. 4 liervor-eachLt _; ejn at the lui sciiluS 14 led to the ε signal , divided ir * in funct a, so that two direct audio frequencies si anals are formed, dis the adders 10 or v ;. 18 'watched. Di = direct audio frequency signals four ce η on the other hand to the adding: 16 and 13 'from dun points b or »b ¹ partly also fed via the delay _{circuits 15 or} 15', while the outputs, 'er Y ^ rzc-gerungskreise 15 and 15 'are fed back via the phase shifters 16 and Id ¹ to the adders 17 and 17', respectively. Those from the Yer->; ögerungskreise 15 azw. 15 ¹ and the signals obtained from the phase shifter l6 or <> l6 'represent those signals which correspond to the indirect sound in the loudspeaker before hearing ( i.e. the indirect audio frequency signals), these indirect audio frequency signals verder: in the adders Ic and / or. Lö 'added to the relevant direct audio frequency signals that are transmitted via the signal path 14-ab Όζά. 14 ~ ab ', whereupon in the sound transducers 8 and the headphones 7 ^r, TJjuwandlun ^ occurs in sound, which is finally perceived with ris; .i left and right ears β and 5, respectively.

DLs cbe abe writes ne execution form concerns the case, nz. ^r i ..lit ilonaural signals η is worked. If, on the other hand, it is a question of audio channel stereophonic signals as in the case of the arrangement of the pig. 5 »This is how one divides the Li nies-Ui. ϊ the He ch ts si gnal, which ^{are fed to the input connections η 19 and I9 1} , in two signals each corresponding to the ne η embodiment described above, so that nan over delay circuits 15 15 '? 15 "bzv /. 15"'and phase shifter l6, l6', 16 "bzv;. L6 ^IM ; .i with different frequency-phase characteristics receives four indirect tone frequency signals, and these indirect tone frequency signals and the Signals corresponding to the direct sound are added and fed to the left and right sound transducers 9 or "of the headphones 7. Furthermore, in Fig. 5 with the reference numbers 17, 171, 17", 17 "i _{5 16} , 18 1, 18", 18 " i, 20 and 20 each denotes an adder.

In the case of the two-channel stereo signals, the invention can be embodied in a simplified circuit as shown in FIG is.

In Fig. Β are .dt the 3e ^ ugs number η 19 and 19 'input

connections

609882/071 2

BATH ORIGINAL

_ ₆ _

refers to connections to which in a playback system stereo signals are fed, the reference numeral 21 denotes an adder to: .. adding the & 11 the Lin _£ angsanschlüssen 19 and 19 'supplied stereo signals, with the reference number 15 eats a tarry RUX: _: , denotes a phase shifter or a resistor and the reference number 22 denotes an adder, the delay circuit 15 and the phase shifter or resistor Id representing an iischh.i>llbchaltun; ·:. The Lus-BJie of the Y-. delay circuit 15 fed back via the phase shifter l6, ura to generate an indirect Tc frequency signal .dt reverberation effect. The indirect tone frequency signal is attenuated by a control resistor and then fed to adders> 5 "and 25 'via phase shifters 24 and 24' with different phase characteristics the input connections I9 and 19 ^; direct audio frequency signals D, and D ₂ fed to the mentioned indirect audio frequency signals ID, or ID "added and the signals obtained by addition ■ the left and right audio transducers 9" and 8 of the Kovfhörers forwarded.

The tests carried out as part of the inventive efforts have shown that the listener in the arrangement of the Flg. 6 perceives the sound image as lying outside of his head, who.11 the ratio of the indirect audio frequency signal to the direct audio frequency signal amounts to more than 1 in 10. The ratio of the indirect audio frequency signal s to the direct audio frequency signal can be changed by setting the Re gel wide rs tan of 23 and with a gradual change in this ratio to a value of 1 to 10 or more, the perception of distance in the gradually hindered Perception of the sound image.

Fig. 7 is a graphical representation of the change in direction ψ de s hearing image as a function of a change in setting of a Re ge lwi de rs tan des 26 in the arrangement shown in FIG. 8, in which a signal appearing at the input terminals I9 at a point a in two signals is divided, one of which goes to the right audio transducer 8 of the headphones, while the other is routed to the left audio transducer 9 via the Re ge lwi of the stand 26. It is confirmed that the direction angle ψ differed gelunter with increasing Pe

609882/071 2 ^between

between the signals applied to each of the transducers increases.

Ug ₁ 9 the electrical ticket Tung arrangement shows a si: oofh "rersystems, are taken into account, the above-mentioned sparked in the structure The circuit shown in Figure 9 makes it possible to make the acoustic image arising outside of the head, and moreover, the acoustic image can also.. In Fig. 9, the reference numerals 26 and 26 'denote damping oils such as resistances and the reference numbers η 27 and 27' denote adders.

Either by connecting the circuit arrangement shown in FIG the same hearing condition with conventional headphones <] can be conveyed as in the case of speaking before hearing, see above can the eavesdropping still further be perfected by this, that .T., .. n the characteristics of the headphones themselves have a certain shape & ibt, 7; ie this is the case in point B mentioned above.

In the usual loudspeaker reproduction, it is generally desirable that the plotted sound pressure characteristic curve of the loudspeaker in the frequency. The entire range from 20 Hz to 20 kHz is flat. Even with the use of a loudspeaker with such a flat frequency characteristic, however, the sound pressure-frequency characteristic curve fills out in such a way that, due to the resonance of the auditory canal and the diffraction of the sound waves through the head and auricle, two curves appear at peaks at 2 kHz and 4 kHz the pe ge! difference between the curve peaks and the lower level range between 6 dB and 17 dB holds when the loudspeaker 3 is arranged in the manner shown in Fig. 1 at a ⁷ , 7winkel of 30 ° in front of the listener 4 and the sound pressure Frequency characteristic is determined by placing a probe microphone at the entrance of the ear canal of the ear canal 4. In the case of listening with headphones, the same level of hearing can accordingly be achieved as in the case of loudspeaker listening, inde: n iaan headphones are used which have such a sound pressure-frequency characteristic.

In view of the above circumstances, the headphone is carried out according to the invention, apart from that shown in FIG Circuit, using headphones in whose sound pressure

Fre que nz-I-le nnli never

609882/0712

BATH ORIGINAL

i re que η ζ characteristic curve two iZur-vengipfel zvri. see 1.5 kHz and 5 kEz available are, v / obei is the Fegel difference between the curve shapes and the lower Pe yellow rich z .-. is 6 dB and 17 dB.

Headphones with the above league members, for example, come from those in Ii g. 10 have the structure shown.

In Fig. 10, the reference numeral 26 denotes a supporting part., The reference number 2S) denotes a headphone housing attached to the supporting part 28 in a slidably displaceable arrangement is made of elastic material such as plasticized urethane and is provided on the Yoröerfläche of the housing 29, with reference numerals 3Ga and JOb are perforations in the ears; If it is designated 50, the reference number 31 riit a flood with a single attachment 31a. with the reference number 31b an opening provided in the middle η attachment 31a ', with the reference number 32 a magnet, with the reference number 53 an upper plate, with the reference number 34 a fiahaen, v.it the reference numeral 35 ^{in e} vibrating plate, with the 3ezugszahl 36 a Schwing'spule that in the approach between the center 31s. and the upper plate 33 provided magnet gap is arranged, the B ... train number 37 ^s in ien tree between the housing 29 and the loudspeaker recorded damping material, with the 2 reference numbers 38 and 39 are air spaces on both sides of the vibrating plate 35 denotes and the reference numeral 40 denotes a at the upper side de 3 mit ti ge η attachments 31 a- vorge he ne s attenuation sme te ri al.

If one assumes a 7 / ert m for the inertia, which can be traced back to the central opening 31b of the nittigtsn attachment 31a, a 7 / ert m for the cash register of the oscillating plate 35, a value hl for the volume of the swirling coil 36. , for the acoustic resistance to be traced back to the damping material 40 a 'vert r, for the on di.-. ε ear pads 30 traceable acoustic bursting an ΪΛ-rt X ^, fi-'r de ;, to the damping material 37 traceable acoustic 7äd & rstand ei-.en ^T , 7ert r _n , for the through the openings 30a and 3Cb in cJesi Chr cushion 30 conditioned inertances the bank el or Dip, x'ur the acoustic capacity of the air space 3Ö a 7 / ert C, for the acoustic capacity of the air space 39 tine η '7ert G, for the

Radiation impedance

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BATH ORIGINAL

2608U9

Radiation impedance oinen 'Jeτι r ^ and for the control force acting on the oscillation system ^: .7ert F, the equivalent circuit shown in FIG. 11 is obtained. In this embodiment, the curve ng · Lof el at 2 kHz is formed by varying the inertance ji caused by the smock opening 31b du s jüittigen attachment 51a, the curve corner at 4 kHz τ, / is formed by tariing the through the openings 30a and 30b of the ear pad 30 caused inertances iil and m and the overall shape -. «/ Le i These curve peaks are also influenced by a corresponding adjustment of the acoustic resistances r, r and r_; t% one can So the sound pressure frequency characteristic shown in Fig. 12 as a solid line is obtained, which has two curve peaks at 2 kHz and 4 ^ Hs, with the level difference between the ^ urvenginfeln and the lower level range, to 6 dB to 17 The broken line in FIG. 12 represents the characteristic curve in the free blade field in a loudspeaker arrangement such as that shown in FIG essential the si -i before τ. is the one in Fi £. 12 reproduced as a solid line and ^ liurt be.

j-itit ■ ·. [./. ·! i "r-cinn ei.rie j-'linlichie Cha.rakteristik also received be, ir-dem nan the other instances and acoustic resistances f, changes. In any case, it has been confirmed that essentially the same Kürzuutand '.via outdoor sound field can be achieved, though two lurve peaks between 1.5 kHz and 5 kHz are present and themselves the level difference between the upper curve peaks and the lower one ..egfcl range between 6 dB and 17 dB hLlt.

J It other v / places., ..I cO. in the circuit arrangement of Fi ₀ -. 9 worked -lit headphones, in dsren sound pressure Frequenziieurtlinie two iurvengipfel zv / isehen 1.5 kHz and 5 kHz are present, - .: 'the level differences bii d between the cam peaks and de:; i lower Peijulbereich between 6 dB and 17 dB holds, an Eörbild öanz v / ie in the case of loudspeaking audition outside of the head and built up in front of it cast and furthermore the auditory image can also be influenced in any way with regard to the sense of distance and direction

609882/0712 bad original

- IG become fluüt.

13 shows another embodiment of the invention. This embodiment differs from the circuit shown in FIG. 9 in that the outputs of the phase shifters 24 and 24 ^! through low-pass filters 4I and 41 '^ e he η and in each case via adders 42' and 42 your other channel. The reason for the fact that the low-pass filters 41 and 41 'are also provided is that the audio image can be localized more precisely. A;: n.

A further embodiment of the invention is shown in FIG. 14. In Fig. I4 are indicated by the reference numerals 19 and 19 'input terminals for the supply of the ste re ο signals generated by a playback system, ax the reference numerals 15, 15', 15 "and 15"' ^T / delay circles, with the reference numerals ^{16, 16 1} , 16 "and 16 ¹ " phase shifters or resistors, uit the reference numbers 17? 17 '> 17 "and 17"' adder with the reference numerals 18, 18 ', 18 "and 18"' and with the reference numerals 20 and 20 ^J also adder and the reference numerals 43, 43 ', 44, 44', 44 "and 44 '" sail resistance.

In the arrangement of FIG. 14, a signal fed to the input terminal 19 is divided at a point a into two direct audio frequency signals which are sent to the adders 18 and 18 '. The direct audio frequency signals are ^{partially branched off at points b and b 1} and passed through the delay circuits 15 and 15 'and the Ee gel resistors 44 and 44' to the adders 18 and 18 '. The outputs of the delay circuits 15 and 15 'are fed to the adders 17 and 17' via the phase shifters 16 and 16 '. The signals received by the adders 18 and 18 · on the Terzögerungskreise and I5 ¹ and the phase shifter L6 and I6 ^1, are those corresponding to the indirect sounds in the Lautsprecherabhörung (ie the indirect tonf requenzsignale), and the indirect audio signals added in the adders 18 and 18 'to the direct audio frequency signals.

Similarly, a signal fed to the input terminal 19 'is converted into indirect audio frequency signals by the third delay circuits 15 "and 15"' and the phase shifters 16 "and I6 ¹ ", whereupon the indirect audio frequency signals and the direct

th

609882/0712

BATH ORIGIsNAL

t-'ϊΐ [audio frequency signals in the adders 13 "and 18"'are added. JLe ~, .uspi ^: η ge the adder 18 ^! and 18 "were uter the .i of the stands 43 unö 4-T ¹ c ^; en adders 20" resp. 20 'in order to add them to the signals from the other cannula. The outputs of the adders 20 and 20 'i' - iiien to the left and right oton converters 8 and 9 of the headphones 7.

The m , .elvri.derstands 44, 44 '_; 44 "and 44"'are used to set the mixing ratio of the indirect audio frequency signals to the direct audio frequency signals and by changing the resistance values of the resistance 44 »44 ¹ » 44 "and 44"' the audio image hi η calibration can be influenced by the distance sensor. Furthermore, by adjusting the Eegelvri.derstands 43 and 43 'the Eichtwahrr.ehmui.-y of the audio image can be influenced.

The headphone system according to the invention has the top screamed here The structure and the following can thus be achieved according to the invention i ^ kuaiifeH be r submit η ·.

1. De da ε indirect! Audio frequency signal the direct audio frequency ■ .uöii2i: d:; ynal is added in a ratio of more than 1 to 10, we 'li-s-fi Ilcrbild au .'- erh8, lb of the head built up and the bein Heren it I:; oihör-; t;. "iia youth phenomena are omitted.

2. list audio image can be achieved by dividing the attenuation elements H:. can be easily influenced in terms of the distance approach.

⁷ J. The perception of the auditory image can also be easily influenced by setting the Dir / apfungS: lieder.

4 · Lie 1- »φ ds s Ιί-irbildes differs in the ICo ofiiohörunj depending on the I η dividual differences. But can c rf iruiur'-js ^ oiiiU? Achieve an optimal hearing condition without v ^ iteres jev ^ ils.

SAD ORIGINAL patent claims

609882/0712

Claims (13)

-12- 2608U9 Claims l '. Headphones sy stem, characterized by reverberation circuits (lj, Ig. 15 ', l6') and Toiiwandler (8, 9), wherein a transition from a signal of an electro-acoustic "!! Device appearing direct audio frequency signal for generating indirect audio frequency signals the Fschhall schal tunken (15, l6; 15 ', l6') can be fed and the indirect and direct audio frequency signals can be fed to the audio transducers (S, 9). 2. headphone sy s th according to claim 1, characterized in that the reverberation circuits (l5, l6t 15 ', l6') each have a phase shifter (l6j 16 ¹ ) and a delay circuit (15ϊ 15 ') for feedback of the phase shifter output to include at the entrance- 3 · headphone system according to claim 1, characterized in that the indirect audio frequency signals with the direct audio frequency signal each via an attenuator (23) -mixed. A liOpfhörersystem according to claim 3) characterized in that the Attenuator (23) for bringing about a change in the indirect Audio frequency signal s in relation to the direct audio frequency signal in which Yerhilltnis is adjustable from more than 1 to 10, whereby the Hearing image can be influenced in terms of the sense of distance. 5 · Headphone system, characterized by specialist _{reverb circuits (l5 5} l6i 15S Lö '), a left sound converter (9) and a right sound converter (8), the two direct audio frequency signals generated by dividing an IvIo neural signal to generate indirect audio frequency signals Each of the reverberation circuits (l5, 16 * 15 ', I6 ¹ ) can be fed and the two direct audio frequency signals are mixed with the indirect audio frequency signals η and the IiEL signals are sent to the left audio converter (9) and the right audio converter (8) are forwardable. 6. headphone systems, characterized by reverberation circuits (15, Ιο. 15 '»16 ¹ J 15", lö ";15"', 16 "'), a left sound converter (9) and a right sound converter (8) , whereby each of the four direct sound frequency signals generated by dividing the stereo signal of a right channel or the stereo signal of a left channel 609882/0712 - BATH ORIGINAL -I ₅ - 2608U9 for Lrzeugunc four indirect audio frequency signals of the respective reverberation circuits (15, l6-, 15 ', 16' ·, 15 ", l6"% 15 "'» Ιβ ¹¹¹ ) can be fed, the four direct audio frequency signals and the respective of the four indirect audio frequency signals can be mixed with one another to generate four la sch signals η, one of the two:, Iischsignale of the right channel and one of the two lüschsignale of the left channel can be fed to the left audio transducer (9) and the other of the two !, Ii sch signals of the right channel and the other of the two IiL sch signals of the left channel can be fed to the right sound converter (8). 7 · Fo'of earphone system, characterized by a reverberation circuit (l5> l6)., a left tone transducer (9) and a right tone transducer (8), where two as output signals of a two-channel stereophonic system appearing direct audio frequency signals for generating an ML schsignals can be locked to each other, whereby the LiL schi gnal for Generation of an indirect audio frequency signal of the reverberation circuit (15, l6) can be fed, the indirect audio frequency signal Via an attenuator (23) in two indirect audio frequency signals is divisible, the two indirect audio frequency signals obtained by division and each of the two direct audio frequency signals to generate two las cn signals η each with one another can be mixed and wherein the two mixed signals can be fed to the left sound transducer (9) and the right sound transducer (8), respectively are. 8. headphone system according to claim 7 »characterized in that the Attenuator (23) for bringing about a change in the indirect Audio frequency signal s in relation to the direct audio frequency signal can be set in a ratio of more than 1 to 10, with the hearing image being able to be influenced with regard to the sense of distance. 9 · Pigtail receiver system according to claim 7 j characterized in that the both indirect generated by division by the attenuator (23) Audio frequency signals with the two direct audio frequency signals via phase shifters (24, 24 ·) of different phase characteristics are verifiable. 10. Headphone system according to claim 7 5, characterized in that the both 609882/0712 ■ two direct audio frequency signals can be mixed with the other of the two direct audio frequency signals via a first attenuator (26) or a second attenuator (26 ^1). 11. Headphone system according to claim 10, characterized in that the Correction of the auditory image by adjusting the first attenuator (26) and the second attenuator (26 ') can be influenced. 12. headphone system according to claim 9 »characterized in that a Part of each of the outputs of the phase shifter (24, 24 ·) across a low-pass filter (41; 41 ') can be mixed with the signal of the other channel is. 13. headphone system according to claim 7, characterized in that the Tonwandler (8, 9) iron sound pressure-frequency curve with two Curve peaks between 1.5 kHz and 5 KHz have, with the level difference between your level value of the lower level range and where the peak of the curve is between 6 dB and 17 dB. 14 · headphone system, characterized by a first attenuator (43), a second attenuator (43 ')> a third attenuator (44, 441, 44 », 44 ·") »reverberation circuits (15, 16-, 15', lo ' j 15 ", l6" i 15 "'i I6" ¹ ) and headphones (7) ωχΐ a sound pressure-frequency characteristic aiit two curve peaks between 1.5 kHz and 5 kHz, the level difference between the lower level range and the curve peaks between 6 dB and 17 dB, two direct audio frequency obtained by reproducing a program source signals through the first and second attenuator (43, 43 ') are miscible with each other, wherein the direct audio frequency signals indirect for producing audio frequency signals reverberation circuits (15? 16i 15 «, 16 '; 15», 16 "i 15"', I6 ¹ "), the indirect audio frequency signal for generating Ivüsch signals via the third attenuator (44» 44 '»44"»44"' ) can be mixed with the direct audio frequency signals, 7fobei these ML signals the head listeners (7) are zuleifbar, with the indirect audio frequency signals in relation to the direct audio frequency signals in the sense of influencing the audio image with regard to the sense of standing by adjusting the third attenuator (44, 44 ', 44 ", 44'") in the ratio are changeable from more than 1 to 10 and where 609882/071 2 cie; / shrnehnung; srichtunö of the audio image by setting the first and p 4 ^ ') "is influenced. 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